SLA Pro HPF problem

For livingroom sound better than in a theatre.
Post Reply
Message
Author
gyuripa
Posts: 12
Joined: Tue Jan 10, 2017 9:11 am
Location: Slovenia

SLA Pro HPF problem

#1 Post by gyuripa » Wed Apr 12, 2017 5:45 am

Hello!

I finally had some time to work on my SLA Pro. Everything went smooth, according to the plans, until I had too connect the tweeters. They didn't make any sound, but I could hear a very silent hiss from the high pass filter (what I think it came from). As I changed the frequency on the app, so did the audible frequency off the "silent hiss" change.

The tweeters work fine when I connect them directly to the amp.

So my question is, should I change the whole HPF, or is there another solution, for example change just one part of it? If the second will be the case, how can I determine the broken part?

Thanks for the answers in advance.


Here's a picture of the HPF:
Attachments
hpf_sla_pro_resize.jpg

User avatar
Rune Bivrin
Posts: 511
Joined: Tue Aug 19, 2008 5:42 pm
Location: Stockholm, Sweden

Re: SLA Pro HPF problem

#2 Post by Rune Bivrin » Wed Apr 12, 2017 6:34 am

gyuripa wrote:Hello!

I finally had some time to work on my SLA Pro. Everything went smooth, according to the plans, until I had too connect the tweeters. They didn't make any sound, but I could hear a very silent hiss from the high pass filter (what I think it came from). As I changed the frequency on the app, so did the audible frequency off the "silent hiss" change.

The tweeters work fine when I connect them directly to the amp.

So my question is, should I change the whole HPF, or is there another solution, for example change just one part of it? If the second will be the case, how can I determine the broken part?

Thanks for the answers in advance.


Here's a picture of the HPF:
You're missing a (black) wire between the inductor and the 30 ohm resistor (and then on to the drivers).
In build order:
O12 with no tweeter.
3 x WedgeHorns.
2 x Jack 10 without tweeters.
2 x DR250.
2 x 16" T39
1 x Tuba 24
2 x SLA Pro (sort of...)

gyuripa
Posts: 12
Joined: Tue Jan 10, 2017 9:11 am
Location: Slovenia

Re: SLA Pro HPF problem

#3 Post by gyuripa » Wed Apr 12, 2017 7:06 am

I really missed that, thanks.

So, I made the missing connection, but the problem stayed the same. Still not getting a sound from the tweeters. :?

User avatar
Rune Bivrin
Posts: 511
Joined: Tue Aug 19, 2008 5:42 pm
Location: Stockholm, Sweden

Re: SLA Pro HPF problem

#4 Post by Rune Bivrin » Wed Apr 12, 2017 7:36 am

gyuripa wrote:I really missed that, thanks.

So, I made the missing connection, but the problem stayed the same. Still not getting a sound from the tweeters. :?
I doubt any component is broken. It's mainly a question of determining which connections are missing or broken.
Run a separate wire from the negative on the amp to the negative on the drivers. If you get sound then, there's the problem.
If that doesn't help, do the same with the positive terminals. If you get sound then, remove that wire and connect it across the capacitor. If that doesn't help, connect the wire across the 4 ohm resistor. If that still doesn't help, check all your soldering very carefully.

Also, are all the drivers connected in parallel, or do you have a series/parallel configuration? In the latter case, make sure there's a connection between the two halves.
In build order:
O12 with no tweeter.
3 x WedgeHorns.
2 x Jack 10 without tweeters.
2 x DR250.
2 x 16" T39
1 x Tuba 24
2 x SLA Pro (sort of...)

User avatar
Tom Smit
Posts: 6364
Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: SLA Pro HPF problem

#5 Post by Tom Smit » Wed Apr 12, 2017 9:19 am

Did you do it like this?
Untitled.jpeg
TomS

gyuripa
Posts: 12
Joined: Tue Jan 10, 2017 9:11 am
Location: Slovenia

Re: SLA Pro HPF problem

#6 Post by gyuripa » Thu Apr 13, 2017 2:09 am

Rune Bivrin wrote:
gyuripa wrote:I really missed that, thanks.

So, I made the missing connection, but the problem stayed the same. Still not getting a sound from the tweeters. :?
I doubt any component is broken. It's mainly a question of determining which connections are missing or broken.
Run a separate wire from the negative on the amp to the negative on the drivers. If you get sound then, there's the problem.
If that doesn't help, do the same with the positive terminals. If you get sound then, remove that wire and connect it across the capacitor. If that doesn't help, connect the wire across the 4 ohm resistor. If that still doesn't help, check all your soldering very carefully.

Also, are all the drivers connected in parallel, or do you have a series/parallel configuration? In the latter case, make sure there's a connection between the two halves.
Nice approach of testing crossovers! My results (only one tweeter in the chain):

1. - directly from amp to tweeter, + wire to HPF + in, then + HPF out to tweeter --- OK (got normal sound)

2. + directly from amp to tweeter, - wire to HPF - in, then - HPF out to tweeter --- OK

3. - to HPF in then HPF - out, + to HPF in, but after the capacitor straight to the tweeter --- No sound

4. - to HPF in then HPF - out, + after the capacitor through the resistor --- No sound

5. + to HPF in then HPF + out, - to HPF in thean after coil - out --- No sound

6. + to HPF in then HPF + out, - in after coil, - out after resistor --- no sound

Hope this is understandable. But what now? This doesn't make sense to me. I thought that in the case of 1 & 2, 3 &4 should work.
Later I will research on the net about bad soldering and examples of it, and compare it to mine. But then again case 1 and 2.

Did I miss something really important?

And now it's practice time :)

gyuripa
Posts: 12
Joined: Tue Jan 10, 2017 9:11 am
Location: Slovenia

Re: SLA Pro HPF problem

#7 Post by gyuripa » Thu Apr 13, 2017 2:10 am

Tom Smit wrote:Did you do it like this?
Yes, I did it like this.Still bad results. :/

User avatar
Tom Smit
Posts: 6364
Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: SLA Pro HPF problem

#8 Post by Tom Smit » Fri Apr 14, 2017 1:35 am

I have an idea. Hook up to the red and black leads like you normally would. Then, attach a wire to the red wire (+ to the HPF), and touch before and after each solder joint on the +'ve side of the HPF. If that is okay, then attach a wire to the black wire before the HPF, and use the other end to touch the negative side before and after each solder joint right on up to the tweeter. Wherever you gain sound, that is where the bad joint/component is.
I hope this is clear enough to understand.
TomS

Post Reply